KR102113919B1 - Regasification System of liquefied Gas and Ship Having the Same - Google Patents

Abstract

The present invention relates to a liquefied gas regasification system and a ship having the same, a vaporizer for vaporizing liquefied gas discharged from a liquefied gas storage tank by heat exchange with a fruit; A fruit heater that heats the fruit with a heat source and supplies it to the vaporizer; A heat source processing unit that supplies a heat source from a heat source supply source to the heat source heater and heats a low temperature heat source discharged from the heat source heater to recover the heat source source; And a control unit that controls the flow rate of the liquefied gas flowing into the vaporizer or the flow rate of the heat source to control the liquefied gas vaporized in the vaporizer to be suitable for a desired temperature of the customer, and the control unit includes the temperature of the liquefied gas. According to the control of the flow rate of the liquefied gas flowing into the vaporizer or the flow rate of the heat source flowing into the heater, the heating degree of the low temperature heat source discharged from the heater is controlled.

Description

Regasification System of liquefied Gas and Ship Having the Same

The present invention relates to a liquefied gas regasification system and a ship having the same.

As environmental regulations have recently been strengthened, the use of liquefied natural gas, which is close to eco-friendly fuel, among various fuels is increasing. Liquefied natural gas is generally transported through an LNG carrier, where the liquefied natural gas can be stored in a tank of the LNG carrier in a liquid state by lowering the temperature to -162 ° C or less under 1 atmosphere. When the liquefied natural gas is in a liquid state, the volume is reduced to one-sixth of that of the gas, so the transport efficiency can be increased.

However, since liquefied natural gas is generally consumed in a gaseous state rather than in a liquid state, a liquefied natural gas stored and transported in a liquid state needs to be regasified, so a regasification facility is used.

At this time, the regasification facility may be mounted on a ship such as an LNG carrier, FLNG, FSRU, or provided on land, etc. The regasification facility realizes regasification by heating a liquefied natural gas using a heat source such as seawater.

However, since the liquid liquefied natural gas is placed in a cryogenic state close to -160 degrees, if the temperature difference between the heat source and the heat source greatly increases during heat exchange, problems may arise in the durability of the heat exchanger that heats the liquefied natural gas. Also, when liquefied natural gas is heated using seawater, there is a risk of corrosion in the heat exchanger.

Therefore, in recent years, in the process of regasifying the liquefied natural gas stored in the liquid phase, many studies and developments have been made in the direction of simplifying the regasification facilities while stably operating various components.

The present invention was created to solve the problems of the prior art as described above, and the object of the present invention is to prevent environmental pollution when discharging seawater while setting the required temperature of liquefied gas when using indirect vaporization using seawater. It is to provide a liquefied gas regasification system and a vessel having the same.

A liquefied gas regasification system according to an aspect of the present invention, a vaporizer for heat-exchanging liquefied gas discharged from a liquefied gas storage tank with a fruit; A fruit heater that heats the fruit with a heat source and supplies it to the vaporizer; A heat source processing unit that supplies a heat source from a heat source supply source to the heat source heater and heats a low temperature heat source discharged from the heat source heater to recover the heat source source; And a control unit that controls the flow rate of the liquefied gas flowing into the vaporizer or the flow rate of the heat source to control the liquefied gas vaporized in the vaporizer to be suitable for a desired temperature of the customer, and the control unit includes the temperature of the liquefied gas. In accordance with the control of the flow rate of the liquefied gas flowing into the vaporizer or the flow rate of the heat source flowing into the heater, the heating degree of the low temperature heat source discharged from the heater is controlled.

Specifically, the heat source is seawater, and the source of heat source may be sea.

Specifically, the heat source processing unit, a heat source heater for heating the low-temperature heat source discharged from the heat heater with steam; And a boiler that supplies steam to the heat source heater.

Specifically, the control unit reduces the flow rate of the liquefied gas flowing into the vaporizer when the temperature of the liquefied gas is less than or equal to the first reference value. Decrease, and the first reference value may be a value lower than the second reference value.

Specifically, the control unit may perform control by comparing the liquefied gas temperature downstream of the vaporizer with the first reference value or the second reference value.

Specifically, the controller may control such that a difference between a temperature of a heat source supplied from the heat source supply source to the heat source heater and a temperature of a heat source recovered from the heat source heater to the heat source supply source is within a reference range.

The liquefied gas regasification system according to the present invention and a vessel having the same, while controlling the flow rate of liquefied gas so that the liquefied gas is heated to meet the demanded temperature in the seawater indirect vaporization system, the temperature of the seawater returned to the sea in connection with this By properly heating, it is possible to effectively prevent ecosystem disturbance.

1 is a conceptual diagram of a vessel to which a liquefied gas regasification system according to an embodiment of the present invention is applied.
2 is a conceptual diagram of a liquefied gas regasification system according to an embodiment of the present invention.

The objects, specific advantages and novel features of the present invention will become more apparent from the following detailed description and preferred embodiments associated with the accompanying drawings. It should be noted that in this specification, when adding reference numerals to the components of each drawing, the same components have the same number as possible even though they are displayed on different drawings. In addition, in the description of the present invention, when it is determined that detailed descriptions of related known technologies may unnecessarily obscure the subject matter of the present invention, detailed descriptions thereof will be omitted.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Hereinafter, the liquefied gas may be LPG, LNG, ethane, for example, may mean LNG (Liquefied Natural Gas), and the evaporated gas may mean BOG (Boil Off Gas), which is natural vaporized LNG.

In addition, the liquefied gas may be used as a term encompassing both a liquid state or a gas state vaporized or forcibly vaporized below, but the evaporated gas may be used as a term meaning a gas naturally vaporized in a liquefied gas storage tank. Notice that there is.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a conceptual diagram of a vessel to which a liquefied gas regasification system according to an embodiment of the present invention is applied, and FIG. 2 is a conceptual diagram of a liquefied gas regasification system according to an embodiment of the present invention.

Hereinafter, the liquefied gas regasification system 1 of the present invention will be described with reference to FIG. 2 in particular, and the present invention includes a ship S having a liquefied gas regasification system 1 as shown in FIG. 1. will be.

However, at this time, the ship S is an expression that encompasses offshore plants such as FLNG and FSRU, and furthermore, it is noted that the ship S may be replaced with a plant installed on the ground.

1 and 2, the liquefied gas regasification system 1 according to an embodiment of the present invention, a liquefied gas storage tank 10, a vaporizer 20, a fruit heater 30, a heat source processing unit 40 ), And a controller.

The liquefied gas storage tank 10 stores liquid liquefied gas. The liquefied gas storage tank 10 can store liquefied gas at a pressure of about 1 bar or so, and the liquefied gas stored in the liquefied gas storage tank 10 is discharged to the outside of the liquefied gas storage tank 10 and then the vaporizer 20 It can be vaporized by and delivered to the consumer (D).

At this time, the demand source (D) may be an engine or a turbine that produces energy, or may be a city gas, a plant, a general home, etc., but is not particularly limited, and the liquefied gas is delivered to the demand source (D) in a vaporized state by the vaporizer 20 Can be.

The liquefied gas storage tank 10 may be provided in plural, and may be arranged side by side inside the hull. For example, as shown in the figure, at least four liquefied gas storage tanks 10 may be arranged in a certain direction (front-rear direction) inside the hull, but the number or arrangement of the liquefied gas storage tanks 10 is not limited as described above.

The liquefied gas storage tank 10 has a liquefied gas pump 11 therein. The liquefied gas pump 11 may be installed to be submerged in liquefied gas stored in the liquefied gas storage tank 10 as a submerged pump.

The liquefied gas pump 11 discharges the liquefied gas stored inside the liquefied gas storage tank 10 to the outside of the liquefied gas storage tank 10, wherein the liquefied gas may be somewhat pressurized by the liquefied gas pump 11. However, the pressurization by the liquefied gas pump 11 may not be achieved until the required pressure of the demand destination (D). Therefore, as much as the difference between the pressure of the liquefied gas pressurized by the liquefied gas pump 11 and the required pressure of the demand destination D, pressurizing means (pumps, etc.) provided additionally pressurize the liquefied gas.

A liquefied gas supply line L10 may be provided from the liquefied gas pump 11 to a customer D, and a suction drum 12, a vaporizer 20, and the like may be provided on the liquefied gas supply line L10.

At this time, the suction drum 12 is configured to temporarily store the liquefied gas discharged from the liquefied gas storage tank 10 through the liquefied gas pump 11, and when the internal pressure of the suction drum 12 is properly adjusted, the vaporizer 20 ), The liquefied gas inlet pressure and inlet flow rate can be adjusted.

Although the internal pressure of the suction drum 12 is not shown in the drawing, the boil-off gas generated in the liquefied gas storage tank 10 can be adjusted upward as it is delivered to the suction drum 12, and in addition, the internal pressure regulation means widely known in the art Can be used.

In the liquefied gas supply line L10, a gas flow rate control valve 53 of the control unit 50 to be described later may be provided, and the gas flow rate control valve 53 may be used for the vaporizer 20 in the liquefied gas supply line L10. It can be provided upstream. The gas flow control valve 53 controls the flow rate of the liquefied gas flowing into the vaporizer 20, which will be described later.

The vaporizer 20 vaporizes the liquefied gas discharged from the liquefied gas storage tank 10. The vaporizer 20 may be provided on the liquefied gas supply line L10, and may heat the liquefied gas using various fruits.

As an example, this embodiment may use glycol water, fresh water, etc., which do not have a risk of corrosion in heat exchange parts and lines, or may use propane, R134a, CO2, R218, etc., which can utilize latent heat for heat exchange.

The vaporizer 20 may have a two-stream structure having a flow path through which the liquefied gas flows and a flow path through which the fruit flows, and the flow path through which the liquefied gas flows may be connected to the liquefied gas supply line L10 in which the vaporizer 20 is installed. . In addition, the flow path through which the fruit flows may be connected to the fruit circulation line L30 side by side.

At this time, the fruit circulation line (L30) may be provided with a fruit pump (31), a fruit tank (not shown), a fruit heater (30) for supplying the fruit to the vaporizer (20) at an appropriate temperature and flow rate.

The temperature of the liquefied gas vaporized by the vaporizer 20 may be the required temperature of the demand destination D, and may vary depending on the type of the demand destination D, so the temperature of the liquefied gas heated in the vaporizer 20 is particularly limited. I never do that. However, as an example, the vaporizer 20 may be liquefied by heating the liquefied gas to about 10 to 50 degrees to supply it to the customer (D).

Alternatively, a gas heater 21 may be additionally provided downstream of the vaporizer 20. The gas heater 21 may be provided in series downstream of the vaporizer 20 on the liquefied gas supply line L10, and may share fruit with the vaporizer 20.

Therefore, the liquefied gas vaporized in the vaporizer 20 may be in a state that does not meet the demanded temperature of the demanding destination D, and the liquefied gas may be heated to be suitable for the demanding temperature of the demanding destination D in the gas heater 21. Of course, if the liquefied gas is sufficiently heated only with the vaporizer 20, the gas heater 21 can be omitted.

The fruit heater 30 heats the fruit to be used for heating the liquefied gas in the vaporizer 20 to a heat source and supplies it to the vaporizer 20. The fruit heater 30 may be provided on the fruit circulation line L30 provided in the vaporizer 20 described above, and may have the same / similar 2 stream structure as the vaporizer 20. At this time, the fruit heater 30 has a flow of heat and a heat source, and the heat can be heated while exchanging heat with the heat source.

The fruit may be glycol water or the like as described above, and the heat source may be seawater. In this case, the heat source can be supplied from the sea (sea chest), which is the heat source supply source 41, without limitation, and the supply of the heat source will be described in detail below.

The fruit heater 30 heats the fruit using seawater and supplies the heated fruit to the vaporizer 20. The fruit heater 30 is to heat the fruit circulating along the fruit circulation line L30 with sea water, so that the sea water can exchange heat with the fruit cooled by liquefied gas.

Therefore, the seawater cooled in the fruit heater 30 may be in a state different from the temperature of the sea, so it may not be suitable for environmental problems to recover it directly to the sea. In order to solve this, a heat source processing unit 40 to be described later will be provided. Can be.

A fruit pump 31 is provided upstream of the fruit heater 30 in the fruit circulation line L30. The fruit pump 31 may be provided singly or in plural, and in a plurality of cases, may be provided in series or in parallel to back up each other.

The fruit pump 31 may transfer the fruit cooled by the carburetor 20 or the gas heater 21 to the fruit heater 30, and may be of a type in which the load is controlled or a type in which the load is controlled by On / Off.

The heat source processing unit 40 supplies the heat source from the heat source supply source 41 to the heat medium heater 30. The heat source may be seawater as described above, but is not necessarily limited to seawater. However, in the present invention, the heat source may be a material that is supplied from the heat source supply source 41 and then heat-exchanged with the fruit and then recovered to the heat source supply source 41.

The heat source processing unit 40 may transfer seawater supplied from the sea to the heat medium heater 30, and for this purpose, a heat source pump 42 may be provided. The heat source pump 42 may be provided on the heat source supply line L40 connected to the heat heater 30 from the sea (sea chest), and may be disposed the same / similar to the heat pump 31.

The heat source processing unit 40 supplies seawater to the heat medium heater 30 so that the cooled low temperature heat medium is heated by seawater while vaporizing the liquefied gas. Thereafter, the heat source processing unit 40 may recover the cooled seawater to the sea as the heat source supply source 41.

However, as described above, since the seawater heat-exchanged with the fruit has a temperature different from that of the sea, when the cooled seawater is delivered to the sea, environmental pollution in the sea may occur.

Therefore, the heat source processing unit 40 may heat the heat source cooled by the fruit and return it to the sea, and for this purpose, the heat source heater 43 may be provided. The heat source heater 43 heats the low temperature heat source discharged from the heat medium heater 30 and recovers it to the heat source supply source 41.

The heat source heater 43 may be provided in a two-stream structure similar to the heat medium heater 30 and the like, and the low temperature heat source discharged from the heat medium heater 30 may be heated in various ways. For example, the heat source heater 43 is steam. It is possible to heat the low-temperature heat source. At this time, steam may be produced and delivered in the boiler 44.

The boiler 44 may be an auxiliary boiler 44 provided in an engine room or the like in the ship S, and steam may be generated using various fuels. At this time, the fuel may be the aforementioned liquefied gas.

The steam supply line L41 may be connected from the boiler 44 to the heat source heater 43, and the steam generated in the boiler 44 flows into the heat source heater 43 along the steam supply line L41, and then the heat source In the process of heating it may be converted into condensed water and recovered by the boiler 44.

Through these configurations, the heat source processing unit 40 may prevent contamination of the sea by allowing the seawater supplied from the sea to cool while heating the fruit, and then heated again to return to the sea.

The control unit 50 (IAS) controls the flow rate of the liquefied gas flowing into the vaporizer 20 or the flow rate of the fruit to control the liquefied gas vaporized in the vaporizer 20 to meet the required temperature of the customer D. .

The flow rate of the liquefied gas can be adjusted by the gas flow rate control valve 53 provided in the liquefied gas supply line L10, and the flow rate of the fruit is of the heat pump 31 provided in the heat circulation line L30. Although not shown in the load or the drawing, it may be adjusted by a heat flow control valve or the like that may be provided in the heat circulation line L30.

Of course, with respect to the method for the control unit 50 to control the flow rate of the liquefied gas and the fruit, the present invention is not particularly limited in configuration. For example, the control unit 50 may adjust the flow rate of the heat source flowing into the heat medium heater 30 instead of the flow rate of the heat medium, and for this purpose, a heat source flow rate control valve 54 may be provided in the heat source supply line L40. .

The heat source flow control valve 54 is provided upstream of the heat medium heater 30 in the heat source supply line L40, and directly adjusts the flow rate of the heat source flowing into the heat medium heater 30 by opening control, or the heat source supply line L40 ) Is provided in parallel to at least partially bypass the heat heater 30, a heat source may be provided to control the flow rate that bypasses the heat heater 30.

Therefore, the control unit 50 may control the flow rate of the liquefied gas flowing into the vaporizer 20 or the heat source flowing into the heat medium heater 30 according to the temperature of the liquefied gas. At this time, the temperature of the liquefied gas may mean the temperature downstream of the vaporizer 20, and for this purpose, a gas temperature sensor (not shown) may be provided in the liquefied gas supply line L10.

The required temperature of the liquefied gas may vary depending on the type of the customer D, but for example, the required temperature of the customer D may be 5 to 15 degrees C. In this case, the control unit 50 controls the gas flow rate control valve 53 when the temperature of the liquefied gas approaches the lower limit of 5 degrees, reducing the flow rate of the liquefied gas flowing into the vaporizer 20 to increase the heating temperature of the liquefied gas. Can be.

On the other hand, when the temperature of the liquefied gas approaches the upper limit of 15 degrees C due to reasons such as an increase in the temperature of the water in the sea area (heat source temperature rise), the control unit 50, the heat source flow control valve 54 provided in the heat source supply line (L40) By adjusting the opening degree or by allowing at least a portion of the heat source flowing into the heat medium heater 30 to bypass the heat medium heater 30 through the heat source flow rate control valve 54, the flow rate of the heat source entering the heat medium heater 30 is controlled. The temperature of the fruit flowing into the vaporizer 20 can be lowered.

In this way, the control unit 50 reduces the flow rate of the liquefied gas flowing into the vaporizer 20 when the temperature of the liquefied gas is less than or equal to the first reference value, and when the temperature of the liquefied gas is greater than or equal to the second reference value higher than the first reference value, the fruit heater The flow rate of the heat source flowing into 30 may be reduced.

That is, the controller 50 controls the temperature of the liquefied gas downstream of the vaporizer 20 by comparing it with the first reference value or the second reference value, thereby maintaining the temperature of the liquefied gas delivered to the customer D within a preset range. I can do it.

Of course, instead of controlling the gas flow control valve 53 or the heat source flow control valve 54, the control unit 50 can also control the liquefied gas pump 11 or the heat source pump 42. However, in this case, the liquefied gas pump 11 and the like need to be provided as a variable load type (inverter applied) rather than an On / Off type, which increases the cost, and this embodiment uses a valve instead of a variable control of the pump. Therefore, the temperature of the liquefied gas can be properly adjusted with low cost and simple control.

In addition, the control unit 50, while allowing the liquefied gas to meet the required temperature of the demand source (D) through the above control, so that the heat source recovered to the heat source supply source 41 is in a state suitable for the temperature of the heat source supply source (41) Can be.

Specifically, the control unit 50 may control the heating degree of the low-temperature heat source discharged from the heat medium heater 30 in conjunction with controlling the flow rate of the liquefied gas / heat source according to the temperature of the liquefied gas.

For example, the control unit 50 may adjust the opening degree of the steam flow rate control valve 55 provided in the steam supply line L41 in connection with the opening degree of the gas flow rate control valve 53 and the heat source flow rate control valve 54.

When the opening degree of the gas flow rate control valve 53 is lowered, the degree of heating of the heat in the vaporizer 20 may decrease, which means that the degree of heating of the heat source in the heat of the heat heater 30 may decrease. Therefore, the control unit 50 can lower the opening degree of the steam flow control valve 55.

Alternatively, when the opening degree of the heat source flow control valve 54 is lowered, since the flow rate of the heat source flowing into the heat source heater 43 is reduced or the temperature is increased, the opening degree of the steam flow control valve 55 may be lowered.

However, in the above-mentioned case, the opening degree of the steam flow control valve 55 may be variously adjusted according to the state (flow rate, pressure, etc.) of liquefied gas or fruit. In addition, the opening degree of the steam flow control valve 55 can be controlled in combination according to the control values of the gas flow control valve 53 and the heat source flow control valve 54.

Through the control of the steam flow rate control valve 55 of the control unit 50, the present invention can ensure that the heat source cooled by the fruit and heated by steam is returned to the heat source supply source 41 without problems. .

For this purpose, the first heat source temperature sensor 51 and the second heat source temperature sensor 52 may be provided in the heat source supply line L40, and the first heat source temperature sensor 51 may be used before the heat source exchanges heat with the fruit. It is provided at the position (between the heat source pump 42 and the heat medium heater 30), and the second heat source temperature sensor 52 is the position (heat source) before the heat source is heated in the heat source heater 43 and recovered to the heat source supply source 41 Although it may be provided between the heater 43 and the heat source supply source 41, the positions of the first heat source temperature sensor 51 and the second heat source temperature sensor 52 are not necessarily limited to the above.

At this time, the control unit 50 controls the opening of the steam flow control valve 55 based on the opening degree of the gas flow control valve 53 and the heat source flow control valve 54, and controls the first heat source temperature sensor 51, etc. By utilizing, it is possible to control such that the difference between the temperature of the heat source supplied from the heat source supply source 41 to the heat source heater 30 and the temperature of the heat source recovered from the heat source heater 43 to the heat source supply source 41 is within a reference range. have.

As described above, in the present embodiment, while adjusting the heating temperature of the liquefied gas to be suitable for the required temperature of the demand destination D, it is possible to prevent the ecosystem from disturbing when the seawater heating the fruit returns to the sea.

In particular, the ship (S) of the present invention may be FSRU or the like that suspends in one place for a long period of time and serves as a regasification plant, so this embodiment protects the environment by not directly discharging cold seawater by heat exchange with fruit. I can do it.

In the above, the present invention has been described based on the embodiments of the present invention, but this is merely an example and does not limit the present invention, and those skilled in the art to which the present invention pertains will not depart from the essential technical content of the present embodiment. It will be appreciated that various combinations or variations and applications not illustrated in the examples are possible in the scope. Accordingly, technical contents related to modifications and applications that can be easily derived from the embodiments of the present invention should be interpreted as being included in the present invention.

S: Ship D: Customer
1: Liquefied gas regasification system 10: Liquefied gas storage tank
11: Liquefied gas pump 12: Suction drum
L10: Liquefied gas supply line 20: Vaporizer
21: gas heater 30: fruit heater
31: Fruit pump L30: Fruit circulation line
40: heat source processing unit 41: heat source supply
42: heat source pump 43: heat source heater
44: boiler L40: heat source supply line
L41: Steam supply line 50: Control
51: first heat source temperature sensor 52: second heat source temperature sensor
53: gas flow control valve 54: heat source flow control valve
55: steam flow control valve

Claims (7)

A vaporizer that heats and vaporizes the liquefied gas discharged from the liquefied gas storage tank with a fruit;
A fruit heater that heats the fruit with a heat source and supplies it to the vaporizer;
A heat source processing unit supplying a heat source from a heat source supply source to the heat source heater, and heating a low temperature heat source discharged from the heat source heater to recover the heat source source; And
When the temperature of the liquefied gas at the downstream of the vaporizer is less than or equal to the first reference value, the flow rate of the heat source flowing into the heater is increased, and when the temperature of the liquefied gas at the downstream of the vaporizer is greater than or equal to the second reference value, the flow rate of the heat source flowing into the heating heater It includes a control unit for controlling the liquefied gas vaporized in the vaporizer to be suitable for the required temperature of the customer,
The first reference value is a value lower than the second reference value,
The control unit, in conjunction with controlling the flow rate of the heat source flowing into the heat heater according to the temperature of the liquefied gas, by adjusting the heating degree of the low-temperature heat source discharged from the heat heater, from the heat source supply to the heat heater Liquefied gas regasification system characterized in that the difference between the temperature of the supplied heat source and the temperature of the heat source recovered from the heat source processing unit to the source of heat is within a reference range. According to claim 1,
The heat source is seawater,
The source of heat is liquefied gas regasification system, characterized in that the sea. According to claim 1, The heat source processing unit,
A heat source heater for heating the low temperature heat source discharged from the fruit heater with steam; And
Liquefied gas regasification system comprising a boiler that supplies steam to the heat source heater. According to claim 1,
A liquefied gas regasification system further comprising a gas heater that additionally heats the liquefied gas that has passed through the vaporizer by sharing the fruit downstream of the vaporizer. delete delete A ship characterized by having the liquefied gas regasification system according to any one of claims 1 to 4.

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